This invention relates to a transfer device having a tool mounting surface movable in a generally inverted U-shaped path between two stations, and deals more particularly with such a device having an improved means for obtaining such U-shaped path of movement.
The transfer mechanism of this invention may be used in various different applications where it is desired to move a part or other thing from one station to another. It was initially designed, and is so shown herein, for use as part of a pick and place device used for conveying parts through a U-shaped path from a first station to a second station as, for example, in association with an automatic assembly machine where the parts are supplied by a feeder to the first station and wherein the second station consitutes a delivery station from which the part is taken automatically for further work or assembly with other parts. The transfer machanism includes a tool mounting surface movable in the desired U-shaped path and when the mechanism is used as part of a pick and place device a suitable tool such as a gripper, vacuum head, electromagnet or the like is attached to such mounting surface for grasping an article at the first station, for holding it during movement to the second station and for releasing it at the second station.
Among various pick and place devices proposed in the past an exemplary one is shown by U.S. Pat. No. 4,095,699. Such devices generally are expected to perform their operations through thousands or millions of cycles and therefore should be of a rugged, reliable construction and drivable with a minimum amount of power. The general object of this invention is, therefore, to provide such a device which is of such a construction and yet is capable of being relatively easily and economically manufactured while being of very smooth operation. That is, in the device of the invention the acceleration and deceleration of the tool mounting surface is quite smooth so as to avoid or minimize shocks and vibration and to allow the device to be driven with a low amount of driving force.
Another object of the invention is to provide a transfer mechanism of the above character wherein there is no possibility of the motions of the movable parts getting out of sequence relative to one another.
Also, a more specific object of the invention is to provide a transfer mechanism of the above character having two bodies slidable in two coordinate directions and driven by a common crank arm in such a manner that their motions along their respective axes consist essentially of simply harmonic motions.
Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment taken in conjunction with the accompanying drawings.